Kv9.2

Description: potassium voltage-gated channel, delayed-rectifier, subfamily S, member 2
Gene: Kcns2
Alias: Kv9.2, kcns2

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Introduction

Kv9.2, encoded by HCNS2, is a member 2 of subfamily S of potassium voltage-gated delayed-rectifier channels. Kv9.2 is not functional by itself but can form heteromultimers with member 1 and with member 2 (and possibly other members) of the Shab-related subfamily of potassium voltage-gated channel proteins. NCBI [606]

Experimental data

Rat Kv9.2 gene in CHO host cells datasheet
Click for details 15 °C show 55 cells	Click for details 25 °C show 76 cells	Click for details 35 °C show 58 cells

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Gene

In contrast to the genes in the other subfamilies, members of the Kv8 and Kv9 subfamilies have been found to be incapable of forming functional channels when expressed either in oocytes or cell lines. Moreover, these mammalian genes appear to have no Drosophila homologs. [402]

Species	NCBI gene ID	Chromosome	Position
Human	3788	8	5895
Mouse	16539	15	6052
Rat	66022	7	6070

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Transcript

Species	NCBI accession	Length (nt)
Human	NM_020697.4	5288
Mouse	NM_181317.4	5473
Rat	NM_023966.2	5476

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Protein Isoforms

Species	Uniprot ID	Length (aa)
Human	Q9ULS6	477
Mouse	O35174	477
Rat	Q9ER26	477

Isoforms

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Length (nt)

Protein

Length (aa)

Variant

Isoform

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Post-Translational Modifications

PTM

Position

Type

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Structure

Visual Representation of Kv9.2 Structure
Methodology for visual representation of structure available here

Structure of Kv9.2 ion Channel

The ORFs of Kv9.1 and Kv9.2 encode proteins of 497 and 477 amino acids, respectively, with a calculated molecular mass of 54.9 and 54.3 kDa (Fig. 1 A). Protein sequences reveal that all the structural characteristics of outward rectifier voltage-gated K+ channel α subunits (Kv) are conserved in Kv9.1 and Kv9.2, i.e. six putative transmembrane segments (S1 to S6), a transmembrane region (S4) showing five positively charged amino acids and a conserved pore-forming region (named H5 or P domain). As indicated in Fig. 1 A, Kv9.1 and Kv9.2 subunits contain several putative phosphorylation sites located in the cytoplasmic regions for protein kinase C, cAMP-dependent protein kinase, Ca2+-calmodulin kinase II, casein kinase II, and tyrosine kinase. No N-glycosylation sequence was detected [400]

Kv9.2 predicted AlphaFold size

Species	Area (Å²)	Reference
Human	3754.68	source
Mouse	5659.09	source
Rat	3402.95	source

Methodology for AlphaFold size prediction and disclaimer are available here

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Kinetics

Kinetics of Kv9.2 with Kv2 Family

The time constant of activation of Kv2.1 was not modified by Kv9.1 but it was slightly increased by Kv9.2. No variation of the intensity of the remaining Kv2.1 current after a 9-s inactivation was recorded in the presence of Kv9.1 and Kv9.2. The image bellow shows that the normalized Kv2.2 currents are only slightly modified by Kv9.1 and Kv9.2. The time constant of activation of Kv2.2 was slightly decreased by Kv9.1 and not modified by Kv9.2 [400].

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Expression and Distribution

Kv9.2 Expressed Exclusively in the Brain

Northern blot analysis presented in Fig.2 shows that Kv9.1 and Kv9.2 mRNAs are expressed only in the brain. Specific probes detected two transcripts for Kv9.1 with an estimated size of 2.2 and 2.7 kb and one for Kv9.2 of approximately 5.3 kb. No expression was observed in heart, spleen, lung, liver, skeletal muscle, kidney, or testis [4000]

Inferior Colliculus

Kv9.1 and Kv9.2, two known members of the Kv9 subfamily, appear to be expressed diffusely in cells of the inferior colliculus [400].

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Function

Kv9.1 and Kv9.2 are neuronal modulatory alpha subunits that define a structural family designated as Kv9. They modulate Kv2.alpha subunits but have no functional activity by themselves. [400]. I.e., the kinetics of activation and the voltage-dependence of Kv2.1 currents are altered by such co-expression with Kv9.1 [402].

K+ channel functions are included in very diverse processes such as neuronal integration, cardiac pacemaking, muscle contraction, and hormone secretion in excitable cells [735], as well as in cell proliferation, cell volume regulation, and lymphocyte differentiation [736].

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